Fortifications

Fort Lincoln was one of seven temporary earthwork forts part of the Civil War Defenses of Washington, DC during the Civil War built in the Northeast quadrant of the city at the beginning of the Civil War by the Union Army to protect the city from the Confederate Army. From west to east, the forts were as follow: Fort Slocum, Fort Totten, Fort Slemmer, Fort Bunker Hill, Fort Saratoga, Fort Thayer and Fort Lincoln..

Fort Lincoln was built starting on August 26, 1861 by the First Regiment Massachusetts Volunteer Infantry along the border of the District of Columbia and Prince George's County, Maryland it was named in honor of President Abraham Lincoln by General Order No. 18, A.G.O., Sept. 30, 1861. It was built on the old Baltimore Pike, 2 and 1/2 miles from the city at the time.

The fort had a perimeter of 466 yards (426 m) and places for 34 guns.  ( Source - Wikipedia )